Add support for array index selector

cmd/mustache/main.go

@@ -33,6 +33,8 @@ func main() {
 	rootCmd.Flags().StringVar(&layoutFile, "layout", "", "location of layout file")
 	rootCmd.Flags().StringVar(&overrideFile, "override", "", "location of data.yml override yml")
 	rootCmd.Flags().BoolVar(&mustache.AllowMissingVariables, "allow-missing-variables", true, "allow missing variables")
+	rootCmd.Flags().BoolVar(&mustache.Experimental, "experimental", false, "allow experimental features")
+
 	if err := rootCmd.Execute(); err != nil {
 		os.Exit(1)
 	}

mustache.go

@@ -18,6 +18,10 @@ var (
 	// is true (the default), an empty string is emitted. If it is false, an error
 	// is generated instead.
 	AllowMissingVariables = true
+	// Experimental defines the behavior for experimental features (e.g. commonly
+	// used, but not part of the spec). If it is false (default) it will ignore
+	// the code paths, if true, it will allow you to leverage the experimental features.
+	Experimental = false
 )
 
 // RenderFunc is provided to lambda functions for rendering.
@@ -515,6 +519,19 @@ Outer:
 					return ret, nil
 				}
 				continue Outer
+			case reflect.Slice:
+				if !Experimental {
+					continue Outer
+				}
+				index, err := strconv.Atoi(name)
+				if err != nil {
+					return v, err
+				}
+				ret := av.Index(index)
+				if ret.IsValid() {
+					return ret, nil
+				}
+				continue Outer
 			default:
 				continue Outer
 			}

mustache_test.go

@@ -323,15 +323,15 @@ func TestPartial(t *testing.T) {
 }
 
 /*
-func TestSectionPartial(t *testing.T) {
-    filename := path.Join(path.Join(os.Getenv("PWD"), "tests"), "test3.mustache")
-    expected := "Mike\nJoe\n"
-    context := map[string]interface{}{"users": []User{{"Mike", 1}, {"Joe", 2}}}
-    output := RenderFile(filename, context)
-    if output != expected {
-        t.Fatalf("testSectionPartial expected %q got %q", expected, output)
-    }
-}
+	func TestSectionPartial(t *testing.T) {
+	    filename := path.Join(path.Join(os.Getenv("PWD"), "tests"), "test3.mustache")
+	    expected := "Mike\nJoe\n"
+	    context := map[string]interface{}{"users": []User{{"Mike", 1}, {"Joe", 2}}}
+	    output := RenderFile(filename, context)
+	    if output != expected {
+	        t.Fatalf("testSectionPartial expected %q got %q", expected, output)
+	    }
+	}
 */
 func TestMultiContext(t *testing.T) {
 	output, err := Render(`{{hello}} {{World}}`, map[string]string{"hello": "hello"}, struct{ World string }{"world"})
@@ -716,3 +716,46 @@ func compareTags(t *testing.T, actual []Tag, expected []tag) {
 		}
 	}
 }
+
+var experimental = []Test{
+	{`{{a.b.0.c}}{{a.b.1.c}}`,
+		map[string]interface{}{
+			"a": map[string]interface{}{
+				"b": []map[string]interface{}{
+					{
+						"c": "hello",
+					},
+					{
+						"c": "ehlo",
+					},
+				},
+			},
+		},
+		"helloehlo",
+		nil,
+	},
+}
+
+func TestExperimental(t *testing.T) {
+	// Default behavior, Experimental=false
+	for _, test := range experimental {
+		output, err := Render(test.tmpl, test.context)
+		if err != nil {
+			t.Errorf("%q expected %q but got error %q", test.tmpl, test.expected, err.Error())
+		} else if output != "" {
+			t.Errorf("%q expected %q got %q", test.tmpl, test.expected, output)
+		}
+	}
+
+	// Now set Experimental=true and test again
+	Experimental = true
+	defer func() { Experimental = false }()
+	for _, test := range experimental {
+		output, err := Render(test.tmpl, test.context)
+		if err != nil {
+			t.Errorf("%s expected %s but got error %s", test.tmpl, test.expected, err.Error())
+		} else if output != test.expected {
+			t.Errorf("%q expected %q got %q", test.tmpl, test.expected, output)
+		}
+	}
+}